Abstract: Apparatus for scanning a moving object includes a visible waveband sensor 12 oriented to collect a series of images of the object as it passes through a field of view 16. An image processor 14 uses the series of images to form a composite image. The image processor 14 stores image pixel data for a current image and a predecessor image in the series. It uses information in the current image and its predecessor to analyse images and derive likelihood measures indicating probabilities that current image pixels correspond to parts of the object. The image processor 14 estimates motion between the current image and its predecessor from likelihood weighted pixels. It generates the composite image from frames positioned according to respective estimates of object image motion. Image motion may alternatively be detected by a speed sensor such as a Doppler radar 200 sensing object motion directly and providing image timing signals.

Abstract: A photodetector circuit incorporates an APD detector structure (10) comprising a p? silicon handle wafer (12) on which a SiO2 insulation layer (14) is deposited in known manner. During manufacture a circular opening (16) is formed through the insulation layer (14) by conventional photolithography and etching, and an annular p+ substrate contact ring (18) is implanted in the handle wafer (12) after opening of the window (16). The APD itself is formed by implantation of a p region (20) and an n+ region (22). After the various implantation steps a metallisation layer is applied, and annular metal contacts are formed by the application of suitable photolithography and etching steps, these contacts comprising an annular contact (26) constituting the negative terminal and connected to the p+ substrate contact ring (18), an annular metal contact (28) constituting the positive terminal and connected to the n+ region (22) of the APD, and source and drain contacts (30) and (32) (not shown in FIG.

Abstract: An electronic circuit for Euclidean distance determination includes two floating gate transistors (M1, M2) connected in parallel. Voltages representing a reference point and its complement are applied to input lines (22, 24) and corresponding charges become stored on the transistors' floating gates (F1, F2). Voltages representing a data point and its complement are input to control gates (G1, G2). The transistors (M1, M2) produce a combined output current which is a quadratic or exponential function of the distance between the data and reference points according to whether the transistors are above or below threshold. The circuit (10 ) includes a diode-connected load device (M3) for deriving the square root of the output current, which is proportional to Euclidean distance when the transistors are operated above threshold. Refresh means (M44, M45) may be provided for resetting reference points. An array of circuits of the invention is employed for determination of distances between vector quantities.